About the Transcend SDHC Class 10 8GB memory card

The “Class 10” label on Transcend card suggest that is should work 2½ as fast as the my plain 3 years old Kingston SDHC Class 4 8GB memory card. Indeed, I was disappointed to realize the opposite: Transcend class 10 was on average about twice as slow as Kingstone class 4.

The Transcend SDHC Class 10 8GB memory card was the best compromise among price, speed and capacity. “Class 10” means that the card is expected to read and write data at a rate of at least 10MB/s.

Here are my test results. I used a USB memory card reader that I know to be able to transfer 20MB/s, that is faster that both memory cards. The benchmark was on a P4 computer that is able to handle 20MB/s with ease. After each test, the memory card was removed from the reader to prevent OS caches from affecting the following tests.

Copying a video recording from/to the memory card.

File size: 324MB

Transcend SDHC Class 10 8GB:

Time: 35s to read; 50s to write

Speed: 9,2MB/s to read; 6,5MB/s to write.

Kingston SDHC Class 4 8DB:

Time: 19s to read; 35s to write

Speed: 18MB/s to read; 9,2MB/s to write.

The results show clearly that Kingston SDHC Class 4 8DB is considerably faster than Transcend SDHC Class 10 8GB. The test also suggests that the “Class 10” label from Transcend is an audacious lie!

Copying my portable apps directory (firefox, eclipse, java sdk).

Total size: 878MB, 15540 files

Transcend SDHC Class 10 8GB

Time: 225s to read; 675s to write

Speed: 3,9MB/s to read; 1,3MB/s to write.

Kingston SDHC Class 4 8DB

Time: 161s to read; 542s to write

Speed: 5,5MB/s to read; 1,6MB/s to write.

Copying my eclipse workspace.

Total size: 150MB, 2000 files

Transcend SDHC Class 10 8GB

Time: 48s to read; 87s to write

Speed: 3,1MB/s to read (*); 1,7MB/s to write.

Kingston SDHC Class 4 8DB

Time: 25s to read; 72s to write

Speed: 6,0MB/s to read;2,1MB/s to write.

Lower speed rates are expected due to the large amount of small files that suffer from the access time overhead. But this not an excuse for the lower class Kingston memory card to outperform the higher class Trancend in all test cases. Even worse, the test marked with (*) did not even complete successfully, as the card started failing to read.